Hydraulic system for sequential control of hydraulic motors

ABSTRACT

A hydraulic control system for a self-unloading vehicle having at least a pair of conveyors and beaters operated by individual hydraulic motors for unloading forage from the vehicle body, which preferably utilizes the existing hydraulic pump and reservoir system on a tractor adapted to tow the vehicle and which includes valves adapted to sequentially connect the fluid motors for the conveyors and beaters in a series circuit. One of the valves is connected as a safety valve to stop operation of all of the hydraulic motors. The circuit is arranged so that by reversing the connections of the hydraulic lines to the tractor one of the conveyors can be operated at adjustable speeds in reverse by one of the valves. The hydraulic system is also provided with means to provide the same hydraulic fluid flow rate through the system independent of the output of the tractors hydraulic system so that the self-unloading vehicle may be used with all sizes of tractors.

Unite States Destefan et a1.

atet

[ 1 Feb. 15,1972

Ezolt, State Line; James Martin Benchoff, Waynesboro, all of Pa.

[73] Assignee: Grove Manufacturing Company, Shady Grove, Pa.

[22] Filed: Apr. 9, 1970 [21] Appl. No.: 31,441

Related US. Application Data [62] Division of Ser. No. 745,165, July 16,1968, Pat. No.

[52] US. Cl ..60/52 R, 60/53 R, 91/411 R,

60/52 HE [51] Int. Cl ..Fl5b 11/16 [58] Field of Search ..60/52 R, 53R;9l/411 R [5 6] References Cited UNl'lED STATES PATENTS 2,111,1343/1938 Allin ..60/97 P ux Maloon ...60/52 HE Just et al. ..60/53 RPrimary Examiner-Edgar W. Geoghegan Attorney-Brady, OBoyle & GatesABSTRACT A hydraulic control system for a self-unloading vehicle havingat least a pair of conveyors and heaters operated by individualhydraulic motors for unloading forage from the vehicle body, whichpreferably utilizes the existing hydraulic pump and reservoir system ona tractor adapted to tow the vehicle and which includes valves adaptedto sequentially connect the fluid motors for the conveyors and heatersin a series circuit. One of the valves is connected as a safety valve tostop operation of all of the hydraulic motors. The circuit is arrangedso that by reversing the connections of the hydraulic lines to thetractor one of the conveyors can be operated at adjustable speeds inreverse by one of the valves. The hydraulic system is also provided withmeans to provide the same hydraulic fluid flow rate through the systemindependent of the output of the tractors hydraulic system so that theself-unloading vehicle may be used with all sizes of tractors.

4 Claims, 8 Drawing Figures PATENTEUFEB 15 \912 3.641 .764

SHEET 1 [IF 3 INVENTORS JOHN F. DE FAN JAI .EZ

JAMES RTIN BENCHOFF BY flui 0% 542:

ATTORNEYS PATENTEDFEB 15 I972 SHEET 2 BF 3 HYDRAULIC SYSTEM FORSEQUENTIAL CONTROL OF HYDRAULIC MOTORS CROSS-REFERENCE TO RELATEDAPPLICATION This application is a division of copending application Ser.No. 745,165, filed July 16, I968, now U.S. Pat. No. 3,520,434 issuedJuly 14, I970, for HYDRAULICALLY OPERATED SELF-UNLOADING VEHICLE.

BACKGROUND OF THE INVENTION The present invention is directed to ahydraulically operated self-unloading body which may be either astationary or a transportable body, which consists of a boxlike body orcontainer for discharging, or mixing and discharging, a variety ofproduce materials such as forage, fodder, hay, ear corn, grain, tobacco,etc., in controlled and varying amounts from a selected discharge pointon the body. Self-unloading bodies of the type contemplated herein havebeen known in the art and preferably consist of a large boxlikestructure normally connected on a conventional wagon running gear ortrailer and adapted for towing behind a tractor, or the like. An endlessdeck or apron conveyor is supported by the floor or bed of the body andoperates longitudinally of the body between the sidewalls thereof toconvey produce toward one end of the body. A horizontal transversedischarge conveyor or crossconveyor is mounted on the body adjacent oneend of the deck conveyor to receive the produce conveyed by thatconveyor and is adapted to be operated in opposite directions toselectively discharge produce from opposite sides of the body. Rotatablebeater shafts are also connected on the body spanning the interiorthereof between the body sidewalls and somewhat above the rear portionof the cross-conveyor to regulate the discharge of produce from the deckconveyor onto the endless cross-conveyor. One such self-unloading bodyof the type described is disclosed in U.S. Pat. No. 3,2l4,049, issued toDwight L. Grove on Oct. 26, 1965 and owned by the same assignee as thepresent application. How ever, in the prior art bodies, as illustratedby the mentioned patent. the various conveyors and bearers are driven bya plurality of clutches and endless chain and sprocket gearing driven bythe rotating power takeoff of a towing vehicle. The amount of gearingfor driving the various conveyors is considerable and since there are somany moving parts the gearing requires constant maintenance to maintainthe body in proper operating condition. Several mechanical clutches areprovided in the prior art body for selectively operating thecrossconveyor in opposite directions to discharge the produce fromeither one side or the other of the body and for operating the deckconveyor in opposite direction to discharge produce from a rear end gateon the body, when desired.

The object of the present invention is to provide a hydraulic controlsystem for operating the various conveyors and beaters of aself-unloading body of the type disclosed in the mentioned patent toeliminate the massive mechanical gearing and the plurality of mechanicalclutches, as well as eliminating the need of the potential hazard of therotating power takeoff connection between the self-unloading body andthe towing vehicle. A completely hydraulically operated self-unloadingvehicle having a pair of endless conveyors operating at right angles toeach other has heretofore been unknown in the art and the hydrauliccontrol system of the subject invention renders such a self-unloadingbody more maneuverable, safer and easier to operate and more maintenancefree.

SUMMARY OF THE INVENTION The previously mentioned advantages of thehydraulically operated self-unloading body of the invention are effectedby a hydraulic control system in which separate hydraulic motorsconnected to operate the cross-conveyor, heaters, and deck conveyor aresequentially connected into a series hydraulic circuit by manipulationof three hydraulic valves connected to respectively supply hydraulicfluid to the hydraulic motors only when operated in a predeterminedsequence. The circuit is connected to preferably receive fluid underpressure from the existing hydraulic pump and reservoir system on thetowing vehicle, such as a tractor, with the hydraulic control circuit onthe self-unloading body connected to the hydraulic system on the towingvehicle by means of quick-disconnect connections on the ends of a pairof flexible fluid conduits. The hydraulic valve which controls theoperation of the cross-com veyor hydraulic motor is connected into thehydraulic control circuit at all times and serves as a safety valve toquickly stop operation of all of the conveyors and beaters and theirrespective hydraulic motors, if an emergency arises, during normaloperation of the self-unloading body, such as someone failing into thebody, or the like.

By reversing the pair of flexible fluid conduits connecting thehydraulic control system of the self-unloading body to the hydraulicsystem of the towing vehicle, the deck conveyor may be operated atselected speeds, independent of the crossconveyor and the heaters, todischarge produce from the rear end gate of the body. The hydraulicmotor operating the crossconveyor is also provided with a pair ofquick-disconnect connections connecting the motor into the hydrauliccontrol circuit which may be easily reversed to reverse the connectionof the motor in the circuit to operate the cross-conveyor in theopposite direction. With this arrangement the cross-conveyor candischarge forage or the like from either side of the vehicle and themechanism for accomplishing the operation is much simpler than thereversing clutch and additional chain and sprocket gearing required inthe prior art vehicle.

The hydraulic control circuit for the self-unloading vehicle alsoincludes a selectively adjustable bypass valve arrangement connectedbetween the two fluid conduits connecting the control circuit to thehydraulic pump and reservoir system, which enables the hydraulic controlcircuit to be utilized with hydraulic systems of all sizes on towingvehicles by providing an adjustment to obtain a preselected hydraulicfluid flow rate through the hydraulic control system on theself-unloading vehicle even though the flow rate delivered by the pumpon the towing vehicle is greater than required for the self-unloadingvehicle.

It is within the contemplation of the invention that the hydraulic pumpand reservoir may be contained on the selfunloading vehicle, althoughthey are described and illustrated herein as preferably being containedin the existing hydraulic system on a vehicle used for towing theself-unloading vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified perspectiveview, with parts being broken away, of the hydraulically operatedself-unloading vehicle of the invention;

FIG. 2 is a perspective view, partly in schematic form, showing thearrangement of the hydraulic control system on the body of theself-unloading vehicle;

FIGS. 3A-3D are schematic diagrams of the hydraulic control system ofthe invention and illustrating the flow of hydraulic fluid through thecircuit upon sequential operation of the various valves for effectingthe forward unloading of the vehicle; and

FIGS. 4A and 4B are schematic diagrams similar to FIGS. 3A3D, butshowing the inputs of the hydraulic control circuit from the towingvehicle reversed to effect rear unloading of the body.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, ingreater detail and specifically to FIG. 1, the construction of the basicself-unloading body, exclusive of the drive system, is substantially thesame as that disclosed in U.S. Pat. No. 3,214,049, and the descriptionand disclosure of the detailed construction and mounting of the variousconveyors, heaters, etc., disclosed therein, is relied upon andincorporated herein by reference. The self-unloading body consists of alarge boxlike structure having a horizontal floor or bed 1, verticalsidewalls 2, and a foreshortened forward end wall 3. The rear end wall 4of the body is equipped with a rear end gate 5 of any preferred typewhich can be opened to provide an opening adjacent to the bed when thevehicle is operated to discharge produce from the rear. The body may beentirely open at its top or covered by a roof structure 6 which willallow filling the body with material through an open area above theforeshortened forward end wall.

An endless cross-conveyor 7 is mounted for rotation across the front ofthe body, transversely of the body, and positioned somewhat below thebed 1. A first hydraulic motor 8 is connected to drive one of the rollershafts supporting opposite ends of crossconveyor to cause movement ofthe conveyor transversely of the body. A second hydraulic motor 9 isconnected to sidewall 2 of the body and is connected to rotate the shaftof the lower beater member 10 which is connected transversely of theinterior of the body between the sidewalls 2 and is journaled forrotation within end bearings supported by said walls. One or more upperbeater members 11 in turn are driven in unison with lower beater member10 by chain and sprocket gearing or the like (not shown) connectedbetween the ends of the respective shafts thereon. These vertically,spaced rotating heaters 10 and 11 are driven in unison to continuouslyagitate and break up material which may tend to become caked and theheaters also tend to regulate the passage of material from the deckconveyor 12 onto the crossconveyor 7 beneath lower beater member 10. Theupper beater member 11, or heaters, prevents the material near the topof the boxlike body from sliding forward in great masses onto thecross-conveyor 7, as this would be undesirable. Beaters operating inunison tend to retard the forward movement of the material with the maindeck conveyor 12 and provide a regulated discharge from the lowerportion of the mass of material in the body onto the cross-conveyor.

Endless deck conveyor 12 preferably consisting of longitudinallyextending endless side and intermediate deck or apron chains, connectedby cross flights which engage the material, is connected for rotation onshafts at opposite ends of the bed with one of the shafts being shown at13. A third hydraulic motor 14 is connected through worm gearing 15 torotate shaft 13 and thus rotate the endless deck conveyor 12longitudinally of the body. The deck chains of conveyor 12 have theirtop runs sliding upon the bed 1 from the rear to the front of the bodywhile the bottom runs of the deck chains extend and operate beneath thebody bed 1 with suitable support or slack takeup means, as desired. Deckconveyor 12, when rotated, propels material in the body longitudinallyof the bed toward the cross-conveyor 7 for discharge thereon, orrearwardly of the bed for discharge through rear end gate 5.

The basic self-unloading body can be mounted on a stationary structureor installed upon skids, or as shown in FIG. 1 preferably installed upona conventional wagon running gear or trailer having a draw tongue 16 forconnection to a towing vehicle such as a tractor. The body may also beaffixed to a truck or other self-propelled vehicle. Since all of themovable conveyors or bearers on the body are driven by a hydrauliccontrol system, the body is highly flexible in operation and capable ofavariety of uses.

In the mentioned preferred embodiment, the draw tongue 16 is connectedto a towing farm tractor or the like, and the front axle, not shown, ofthe self-unloading body is a steering axle. The hydraulic control systemof the invention is designed to utilize the existing hydraulic system onthe towing vehicle consisting of a hydraulic pump 17 connected to drawhydrau-.

lic fluid from reservoir 18 and deliver the fluid under pressure from anoutput pressure port 19. A return port 20 is connected to returnhydraulic fluid to the vented reservoir.

The hydraulic control system on the self-unloading body is connected tothe hydraulic system on the towing vehicle by a pair of flexiblehydraulic hoses 21 and 22 terminating in conventional quick-disconnecthydraulic fittings 23 and 24, respectively, for connection with thetowing vehicle output pressure port 19 and return port 20, respectivelyas shown in FIGS. 3A-3D, when it is desired to have the material in thebody unloaded from the front portion thereof by cross-conveyor 7. FIGS.3A-3D therefore illustrate sequential steps in the operation of thehydraulic control circuit for front unloading of the body.

Referring to the hydraulic circuit diagram of FIG. 3A the controlcircuit contains a pair of hydraulic control valves 25 and 26, which arepreferably two-position, push-pull-type valves which are pushed to theirinnermost positions as shown in FIG. 3A in the idle state of thehydraulic control circuit and the self-unloading body. The hydrauliccircuit also contains a turn-type needle valve 27 having a rotatablecontrol knob thereon which is turned counterclockwise to open the valve,as shown in FIG. 3A, before commencing operation of the body. Push-pullcontrol valve 25 is a dual-purpose valve connected to startcross-conveyor 7 when the knob thereof is pulled outwardly and to stopthe conveyor when the knob is pushed in. This valve is also connected inthe main hydraulic fluid supply line from pump 17 and when all conveyorsand heaters are in operation it serves as an emergency safety valve toinstantly stop all mechanical motion when it is pushed in. Push-pullcontrol valve 26 is connected to start operation of the beater members10 and l 1 when the control knob thereof is moved to the outermostposition and to stop operation of the beater members when the controlknob is moved to the innermost position. Needle valve 27 is connected tocontrol the operation of deck conveyor or deck chain 12 at selectedadjusted speeds. The deck conveyor runs at its highest speed when theturn knob of the needle valve is rotated to completely close the valve,and turning the knob in the opposite direction to open the valve slowsthe speed of the deck conveyor 12.

In the idle state of the hydraulic control system and the body, thecontrol knobs of control valves 25 and 26 are pushed to the innermostpositions and the turn knob of needle valve 27 is rotated to open thevalve as shown in FIG. 3A. The hydraulic system on the tractor isengaged and the throttle control of the tractor is set for sufficientr.p.m. so that hydraulic pump 17 delivers approximately 7 or 8 gallonsof hydraulic fluid per minute to control valve 25 through hydraulic hoseor line 21. The hydraulic systems of mediumand smaller-type farmtractors, most commonly used, operate at pressures in the range ofl,500-2,000 psi. and deliver hydraulic fluid at the rate ofapproximately 7 to 8 g.p.m. and the hydraulic control circuit disclosedherein is designed to operate at its maximum efficiency within theseranges of pressure and hydraulic fluid flow. The circuit will operate ata lower rate of fluid flow but the various systems will function at aslower rate. In the idle state of the system, valve 25 directs the fluidsupplied thereto to conduit 28 through direction control check valve 29which is connected to pass the fluid to hydraulic conduit 30 and back toreservoir 18 through hydraulic hose 22, quickdisconnect fitting 24, andreturn port 20.

The control knob of control valve 25 is then moved to the outermostposition as shown in FIG. 3B, cutting off the supply of fluid to conduit28 and directing the fluid through conduit 31, quick-disconnect fitting32, cross-conveyor hydraulic motor 8, quick-disconnect fitting 33,conduit 34, and back to reservoir 18 through control valve 26, conduit28, check valve 29, conduit 30, hose 22, hydraulic fitting 24, andreturn port 20. This operation commences operation of cross-conveyor 7in one direction since it is driven by hydraulic motor 8. The throttlecontrol on the tractor is adjusted to obtain a reasonable unloadingspeed on cross-conveyor 7, and the conveyor is run until it is clearedof all produce or forage material. In this state of operation, 7 or 8g.p.m. of hydraulic fluid are flowing through cross-conveyor hydraulicmotor 8 and the fluid flow path through the circuit is shown by theheavy dark lines in FIG. 38 as well as in the other circuit diagrams.

The control knob of control vaive 26 is then moved from its innermost toits outermost position, as shown in FIG. 3C, cutting off supply ofhydraulic fluid to conduit 28 from conduit 34 and directing that fluidflow through second hydraulic motor 9 to start the operation of beatermembers 10 and 11 connected thereto. Control 26 thus connects hydraulicmotor 9 in a series hydraulic circuit with hydraulic motor 8, and thehydraulic fluid output from motor 9 is returned to reservoir 18 throughconduit 35, open needle valve 27, conduit 30, and elements 22, 24 and20. When beater members 10 and 11 are running free of the produce orforage material in the body the endless deck conveyor 12 is actuated tocommence movement of the mass of material forwardly toward thecross-conveyor 7 by rotating the turn knob of needle valve 27 in aclockwise direction to progressively close the valve, as shown in FIG.3D, to divert the hydraulic fluid output of motor 9 in conduit 35through third hydraulic motor 14 which operates deck conveyor 12. Needlevalve 27 is closed to a point until the desired speed of deck conveyor12 is obtained to give a satisfactory unloading speed of material fromthe body. The deck conveyor moves material onto the cross-conveyor andit unloads that material from one side of the vehicle. The speed of thedeck conveyor determines the amount of material deposited on thecross-conveyor and thus the unloading rate of the material from the bodyand needle valve 27 enables the operator to selectively adjust the speedof the deck conveyor. As indicated by the broken line at 36 in FIG. 3D,during normal body unloading operation, the entire hydraulic fluid flowoutput from motor 9 is not directed through motor 14 as needle valve 27bypasses a portion of the fluid around motor 14 where it then combineswith the fluid output from motor 14 and is returned to reservoir 18through conduit 30, hose 22, fitting 24 and return port 20.

No other adjustments of the valves are necessary until the body isnearly emptied of material and the feeding of material from the deckconveyor onto the cross-conveyor becomes light. The turn knob of needlevalve 27 is then rotated further clockwise to close the valve to greaterextent, and possibly close it completely, until a good sweep-speed ofdeck conveyor 12 is achieved to complete the unloading of the body. Itis to be noted that increasing the rpm. of the tractor will also speedup deck conveyor 12 and raise the sweep-speed thereof, since thisincreases the flow rate of hydraulic fluid through deck conveyorhydraulic motor 14.

When unloading of the body has been completed the control knobs ofcontrol valves 25 and 26 are pushed to their innermost positions, andthe turn knob of needle valve 27 is rotated counterclockwise to open theneedle valve, as shown in FIG. 3A. The body and the hydraulic controlsystem in this state is again ready to receive the next load ofmaterial.

If it is desired to have cross-conveyor 7 operate in the oppositedirection to unload material from the opposite side of the body, it isonly necessary to reverse the connection of the two quick-disconnectfittings 32 and 33 which connect crossconveyor hydraulic motor 8 intothe control circuit. This reversal of connections is done before thehydraulic circuit is energized and it reverses the rotation of motor 8which in turn reverses the direction of travel of the cross-conveyor.The two quick'disconnect fittings 32 and 33, as well as the controlvalves 25, 26 and 27, are conveniently located on the forward end ofwall 3 of the body immediately behind and within easy reach of theoperator on the towing vehicle. If an emergency arises during operationof the self-unloading vehicle, such as someone, or some object, fallinginto the vehicle in the vicinity of the heaters or the conveyors, it isonly necessary for the operator to turn around and push-in the controlknob of control valve 25 to instantly stop all mechanical motion in thebody and return the control circuit to the idle state as shown in FIG.3A. The control knob for this valve can be appropriately colored to makeit prominent and to distinguish it from the other valves.

From FIGS. 3A-3D it can be appreciated that the circuit is designed froma safety standpoint as the various valves must be operated in a definitesequence in order to operate the unloading systems. This is a deterentagainst inexperienced operators damaging the unloading systems, orchildren playing around an idling unloading system from becoming injuredor causing damage to the unloading systems. For instance, if controlvalve 26 is actuated before control valve 25, none of the unloadingsystems will be activated. This prevents the possibility of bending thebeater members by rotating them in a mass of material forwardly of thebody which has not been cleared away by the cross-conveyor. Also,operation of needle valve 27 before operation of both control valves 25and 26 will not result in activation of any of the unloading systems.Control valve 25 must first be pulled out before any of the systems willoperate and by pushing-in on this valve all of the unloading systems inoperation will be immediately stopped.

To operate the self-unloading body to discharge material from the rearthereof, the rear end gate is unlatched and secured in an open positionproviding a sufficiently wide opening to allow discharge of material tothe rear of the vehicle. As shown in FIGS. 4A and 4B, the connections ofthe flexible hoses 21 and 22 with the output pressure port 19 and returnport 20 of the hydraulic system on the tractor are reversed from theconnections used for front unloading of the body as shown in FIGS.3A-3D, with quick-disconnect fitting 24 of flexible hose 22 connected tooutput pressure port 19 and quick-disconnect fitting 23 of flexible hose21 connected to return port 20.

With needle valve 27 in the open position, the hydraulic system on thetractor is engaged and the throttle is set for sufficient r.p.m. so thatpump 17 delivers approximately 7 or 8 gallons of hydraulic fluid perminute through elements 19, 24, 22, conduit 30, open needle valve 27,return conduit 37, direction control check valve 38 which is moved tothe open position, flexible hydraulic hose 21 and elements 23 and 20,back to reservoir 18. This is the idle state of the hydraulic controlcircuit as shown in FIG. 4A, arranged for rear unloading of the body.With valve 27 open hydraulic fluid does not pass through hydraulic motor14 because the open valve is the path of least resistance. Since controlvalve 26 is pushed to its innermost position it blocks movement ofhydraulic fluid through conduit 35 and hydraulic motor 9, and thehydraulic fluid flow in conduit 30 retains check valve 29 in closedposition to prevent fluid flow in conduit 28 to the valves 25 and 26since the check valve is connected in the circuit only to allow passageof fluid in the direction of conduit 30 from conduit 28.

As shown in FIG. 4B the turn knob of needle valve 27 is then rotatedclockwise to gradually close the valve and this restriction in thehydraulic line causes a portion of the hydraulic fluid to flow throughdeck conveyor hydraulic motor 14 to operate deck conveyor 12 in areverse direction to move material toward and out of the open end gate5. Needle valve 27 is adjusted toward the closed position until adesired unloading speed of the deck conveyor is attained.

An alternate method for rear unloading of the body is to completelyclose needle valve 27 so that the entire hydraulic fluid flow isdirected through hydraulic motor 14. The unloading speed of the deckconveyor is then controlled by adjusting the throttle of the tractor.Increasing the rpm. of the tractor will speed up the unloading of thebody as this increases the rate of flow of hydraulic fluid in the systemfrom pump 17, and decreasing the rpm. of the tractor will slow down theunloading of the body. To stop the rear unloading needle valve 27 mustbe opened or the hydraulic pump system on the tractor must bedisengaged.

In order to operate the hydraulic control circuit of the invention withlarger size tractors having hydraulic systems delivering hydraulic fluidat higher rates than the 7 or 8 g.p.m. required for operating thesubject system, that is, for example, systems which deliver fluid at therate of 15 to 20 g.p.m., a normally closed turn-type needle valve 39,similar to valve 27, is connected in the circuit between hydraulic hoses21 and 22. In order to reduce the higher rate of flow of hydraulic fluidto that needed to operate the self-unloading body, the needle valve isgradually opened, as shown in the dotted position in FIG. 3D, to passthe excess How of hydraulic fluid supplied through output pressure port19 from pump 17 immediately back to reservoir 18 through hydraulic hose22, fitting 24 and return port 20. Needle valve 39 thus functions tometer out the 7 or 8 g.p.m. flow rate to control valve 25 that isrequired to operate the unloading systems and returns the excesshydraulic fluid back to the tractor reservoir.

It is to be understood that the hydraulic pump 17 and reservoir 18 canbe a part of the self-unloading vehicle rather than remote therefrom ona towing vehicle. The terms and expressions which have been employedherein are used as terms of description and not of limitation, and thereis no intention, in the use of such terms and expressions, of excludingany equivalents of the features shown and described or portions thereofbut it is recognized that various modifications are possible Within thescope of the invention claimed.

What we claim is:

l. A hydraulic control system; comprising a constant displacement pumpadapted to supply a flow of hydraulic fluid; a reservoir of hydraulicfluid connected to supply said pump; first, second and third hydraulicmotors each having an inlet and an outlet port; first, second and thirdcontrol valve means respectively alternately connected in series circuitbetween said pump, the ports of said first and second hydraulic motorsand said reservoir; the ports of said third hydraulic motor connectedacross said third control valve means; each of said control valve meanshaving an input and movable between a first position directing thehydraulic fluid at the valve input to said reservoir and a secondposition directing the hydraulic fluid at the valve input to thesucceeding hydraulic motor means in the series circuit so thatsequential movement of said first, second and third control valve meansto the second position successively operatively connects said first,second and third hydraulic motor means in series; whereby said firstcontrol valve means must be moved to its second position before any ofsaid hydraulic motor means are actuated and upon moving said firstcontrol valve means to its first position movement of all actuatedhydraulic motor means is stopped.

22. A hydraulic control system as set forth in claim 1 in which theinput of said first control valve means is connected to receivehydraulic fluid from said pump, said first and second control valvemeans each having first and second outputs corresponding to said firstand second positions of said valves, said second output of said firstcontrol valve means connected to the inlet port of said first hydraulicmotor means, the outlet port of said first hydraulic motor meansconnected to the input of said second control valve means, said secondoutput of said second control valve means connected to the inlet port ofsaid second hydraulic motor means, and the outlet port of said secondhydrauiic motor means connected to the input of said third control valvemeans and the inlet port of said third hydraulic motor means.

3. A hydraulic control system as set forth in claim 1 in which saidthird control valve means is normally open in said first position, saidthird control valve having a range of openings between said first andsecond positions and adjustable toward said second position to increasethe speed of said third hydraulic motor means.

4. A hydraulic control system as set forth in claim 2 includingquick-disconnect coupling means connected to said inlet and outlet portsof said first hydraulic motor means, whereby the connection of the inletand outlet ports of said first hydraulic motor means to said first andsecond control valve means are reversible by said quick-disconnectcoupling means to reverse the direction of operation of said firsthydraulic motor means.

1. A hydraulic control system; comprising a constant displacement pumpadapted to supply a flow of hydraulic fluid; a reservoIr of hydraulicfluid connected to supply said pump; first, second and third hydraulicmotors each having an inlet and an outlet port; first, second and thirdcontrol valve means respectively alternately connected in series circuitbetween said pump, the ports of said first and second hydraulic motorsand said reservoir; the ports of said third hydraulic motor connectedacross said third control valve means; each of said control valve meanshaving an input and movable between a first position directing thehydraulic fluid at the valve input to said reservoir and a secondposition directing the hydraulic fluid at the valve input to thesucceeding hydraulic motor means in the series circuit so thatsequential movement of said first, second and third control valve meansto the second position successively operatively connects said first,second and third hydraulic motor means in series; whereby said firstcontrol valve means must be moved to its second position before any ofsaid hydraulic motor means are actuated and upon moving said firstcontrol valve means to its first position movement of all actuatedhydraulic motor means is stopped.
 2. A hydraulic control system as setforth in claim 1 in which the input of said first control valve means isconnected to receive hydraulic fluid from said pump, said first andsecond control valve means each having first and second outputscorresponding to said first and second positions of said valves, saidsecond output of said first control valve means connected to the inletport of said first hydraulic motor means, the outlet port of said firsthydraulic motor means connected to the input of said second controlvalve means, said second output of said second control valve meansconnected to the inlet port of said second hydraulic motor means, andthe outlet port of said second hydraulic motor means connected to theinput of said third control valve means and the inlet port of said thirdhydraulic motor means.
 3. A hydraulic control system as set forth inclaim 1 in which said third control valve means is normally open in saidfirst position, said third control valve having a range of openingsbetween said first and second positions and adjustable toward saidsecond position to increase the speed of said third hydraulic motormeans.
 4. A hydraulic control system as set forth in claim 2 includingquick-disconnect coupling means connected to said inlet and outlet portsof said first hydraulic motor means, whereby the connection of the inletand outlet ports of said first hydraulic motor means to said first andsecond control valve means are reversible by said quick-disconnectcoupling means to reverse the direction of operation of said firsthydraulic motor means.